What is the primary purpose of a run capacitor in motors?

The primary purpose of a run capacitor in motors is to provide a phase shift. In alternating current (AC) motors, especially single-phase induction motors, the run capacitor creates a phase difference between the current in the start winding and the current in the run winding. This phase shift is essential because it improves the motor's efficiency and performance by allowing for a more balanced magnetic field, which enhances the motor's ability to produce torque while running.

By creating this phase shift, the run capacitor contributes to smoother operation and helps the motor maintain its speed under varying load conditions. Additionally, it allows the motor to use electrical energy more effectively, which can lead to decreased energy consumption and improved overall performance.

While other components such as starting capacitors may be responsible for providing high starting torque, the run capacitor serves specifically to support the continuous operation of the motor.